CHARACTERIZATION OF A TUNABLE OPTICAL PARAMETRIC OSCILLATOR LASER SYSTEM FOR MULTIELEMENT FLAME LASER-EXCITED ATOMIC FLUORESCENCE SPECTROMETRY OF COBALT, COPPER, LEAD, MANGANESE, AND THALLIUM IN BUFFALO RIVER SEDIMENT

A pulsed (10 Hz) optical parametric oscillator (OPO) laser system base d on beta-barium borate (BBO) crystals and equipped with a frequency-d oubling option (FDO) was characterized for use in laser excited atomic fluorescence spectrometry (LEAFS). This all-solid-state laser has a n arrow spectral line width, a wide spectral tuning range (220-2200 nm), and a rapid, computer-controlled slew scan of wavelength (0.250 nm s( -1) in the visible and infrared, and 0.125 nm s(-1) in the ultraviolet ). The output power characteristics (15-90 mJ/pulse in the visible, 1- 40 mJ in the infrared, and 1-11 mJ in the ultraviolet), laser pulse-to -pulse variability (3-13% relative standard deviation, RSD, of the las er pulses), conversion efficiency of the FDO (2-17%), and spectral ban dwidth in the visible spectrum (0.1-0.3 cm(-1)) were measured. The las er was used as th excitation source for a flame LEAFS instrument of wh ich rapid, sequential, multielement analysis was demonstrated by slew scan of the laser. The instrument allowed about 640 measurements to be made in about 6 h, with triplicate measurements of all solutions and aqueous calibration curves, which yielded accurate analyses of a river sediment (National Institute of Standards and Technology, Buffalo Riv er Sediment, 2704) for five elements with precisions <5% RSD. Comparab le or improved flame LEAFS detection limits over literature values wer e obtained for cobalt (2 mg mL(-1)), copper (2 ng mL(-1)), lead (0.4 n g mL(-1)), manganese (0.2 ng mL(-1), and thallium (0.9 ng mL(-1)) flam e LEAFS.